Means for controlling the fire of automatic guns carried by aircraft



March 18 1924. 1,486,909

0. D. LUCAS MEANS FOR CONTROLLING THE FIRE OF AUTOMATIC GUNS CARRIED BY AIRCRAFT Filed Sept. 29. 1922 Patented Mar. 18, 1924.

UNITED STATES 1,486,909 PATENT OFFICE.

ownn DAVID LUCAS, or LONDON, nnennnn, wns'rmms'rnn, ENGLAND, A

ASSIGNOR TO -VICKERS LIMITED, OF BRITISH COMPANY.

MEANS FOR CONTRdLLING' THE FIRE AUTOMATIC GUNS CARRIED BY AIRCRAFT.

Application filed September 29, 1922. Serial N 0. 591,210.

To all whom it may concern.-

Be it known that I, OWEN DAVID LUoAs, a subject of the King of Great Britain, residing at 49 Linden Gardens, London, W., England, have invented new and useful Improvements in or Relating to Means for Controlling the Fire of Automatic Guns Carried by Aircraft, of which the following is a specification.

This invention relates to means for controlling the fire of aircraft automatic guns which are intended to fire between the blades of the propeller and which use electrically ignited ammunition or percussion ammunition, the striker releasing mechanism in the latter case being operated by an electro magnet or the like. Hitherto it has been proposed to use a commutator or similar device mounted on or geared to the propeller 2 shaft in such a manner that the electric current is allowed to pass only at such a moment that the shot will miss the propeller, the current either igniting the primer 1n the cartridge in the case of electrically ignited ammunition or releasing the striker as stated above in the case of percussion ammunition. It has'been found that under these conditions, in order to provide for the angle of lag at .high propeller speeds and for the 3 width of the blade, the permissible angle of contact of the commutator is extremely small, -with the result that the firing circuit is completed and the current applied for a very short period of time. Ihe gun itself has also been so constructed that it auto matically closes a local contact in the firing circuit after the breech has been locked, to prevent premature firing of the cartridge. As the gun works in its own period and is independent of the speed of the propeller, it

is possible that the commutator may be about to break circuit at the moment the gun is making it after the breech is closed. In this event the durationof application of the current would be exceedingly short. It will be obvious that the shortestpermissible duration of application of the current irrespective of all external conditions is, in the case of percussion ignition, the time taken to energize and operate the electro-magnetic releasing mechanism of the striker whilst, in the case of electrically ignited ammunition, it is the time necessary tocause ignition of the primer. In the case of electrically ignited ammunition it has been found by contact in the actual tests that this time is of the order of 1/1000th of asecond. It has further been found, that the permissible angle of electrical case of a two bladed propeller is of the order of 9 and, assuming the propeller is rotating at 1,200 revolutions per minute, the duration of application of'the current is 1/800th ofa second on the assumption that the gun has closed its local contact so as to receive the current during the whole of the 9; the time of con tact of the commutator is therefore of the same order as the time required to ignite the cartridge and consequently cannot be materially reduced. I

According to the present invention the controlling means are of such a character that the moment of application of the electric current is determined by the position of the blades of the propeller in conjunction with the position of the gunmechanism, whilst the duration of application of the current is determined in the case of electrically ignited ammunition by the time the ammunition requires for its explosion and in the case of percussion ammunition by the time the electro-magnetic striker releasing mechanism takes for its operation.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be described more fully with reference to the accompanying drawings, in which Figure 1 is a view illustrating diagrammatically one form of the invention as applied to a gun using electrically ignited ammunition the parts being shown in the firing position.

igure 2 is a view similar to Figure 1 showing the parts in the position they 00- cupy after firin Figure 3 is a view similar to the preceding figures showing-a firing key adjusted to the safe position,

Figure 4 is a view similar to Figure 1 illustrating the invention as applied to a gun using percussion ammunition,

Figure 5 is an elevation showing a constructional form of the firing key, and

Figures 6, 7, 8 and 9 are views similar to Figures 1, 2, 3 and 4 showing another form of the invention.

Referring to Figures 1 to t A is the aforesaid commutator device rotated from the propeller shaft, this device in the example circuit, as will be seen from Figure 2, is only -moved away from a fixed shown comprising a disc having a notch to accommodate a projection on a spring contact arm A This contact arm is moved by the disc against a fixed contact a when the disc is in any but the firing position shown by Figure 1 and moves away from this contact when the disc is in the said firing position. B is a sprin contact arm operated by a portion B of the gun breech mechanism in such a manner that the said arm is contact I) as shown in Figure 1 when the gun is ready for firing; when the breech mechanism moves rearwards on firing the gun the contact arm B moves into contact with the fixed contact I) as shown in Figure 2. The said portion B is carried by a contact block B forming art of the firing circuit for the cartridge w ich is indicated at b C is the aforesaid magnetically operated switch and C is the coil for operating it. This switch is spring controlled and in the firing condition occupies the position shown in Figure 1 in which the firing circuit is completed through the intermediary of the said switch. In this condition of affairs it will be seen that the energizing current through the coil C is cut off by the contact arms A and B. The disc A driven by the propeller continues to rotate and thereby moves the arm A against the contact a without, however, completing the controlling circuit through the coil C which completed when the contact arm B has moved against the contact Z) as a result of recoil of the breech mechanism. The energization of the coil C moves the switch G into the position shown in Figure 2 to break the firing circuit. It is by these means that, as aforesaid, the contact arms A and B determine the moment of application of the firing current, whilst the cartridge determines the duration of the current since the current flows through the firing circuit in spite of the altered position of the disc A until the gun has fired. The source of electrical sup ly is indicated at D and it will be observed t lat this supplies current both for the firing circuit and for the controlling circuit.

The arrangement shown in Figure 4 is generally similar to that of Figures 1, 2 and 3 except that the firing circuit contains an electro-magnet 13* serving to release the striker or firing pin of the gun.

A manually operated firing key is provided constituted by two switch arms 6, 6 the former being arranged in the controlling circuit and the latter in the firing circuit. The switches are so constructed that the switch arm e appertaining to the controlling circuit is closed before the switch arm a appertaining to the firing circuit is closed and is opened after the latter switch has been closed. In moving the keyto the firing position the controllin circuit switch arm 6 first closes the contro ling circuit, thus causing the aforesaid switch 0 to break the firing circuit, which is also broken by reason of the fact that the firing circuit switch arm 6 occupies the open position. Further movement of the firing key then closes the firing circuit switch arm 6 and opens the controlling circuit switch arm 6, the said switch C remaining in its open position unless in the meantime the controlling circuit has been broken by the aforesaid arms A and B. In Figures 1 to 4 the firin key is shown purely diagrammatically; Figure 5 however shows a form that this key may take. In this figure 0, 0 represent the contact arms of the controlling circuit and the firing circuit respectively as in Figures 1 to 4, but these arms are stationary. as is also a third arm e connected to the positive of the battery D. The movable element is constituted by an insulating drum E having three electrically interconnected contact strips e e 6 The key is shown in the safe position. Rotation of the drum E in the direction of the arrow first establishes connection between the battery and the controlling circuit, then establishes connection between the battery and both the controlling and the firing circuits and finally maintains the connection between the battery and the firing circuit and breaks the connection between the battery and the controlling circuit.

Referring to Figures 6 to 9 the contact arm A is moved by the disc A away from a fixed contact a when the disc is in any but the firing position shown by Figure 6 and moves against this contact when the disc is in the said firing position. The spring contact arm B operated by a portion B o the gun breech mechanism is moved against the fixed cont-act Z) as shown in Figure 6 when the gun is ready for firing; when the breech mechanism moves rearwards on firing the gun the contact arm B moves away from its contact I) as shown in. Figure 7. The switch C is spring controlled and in the firing condition occupies the position shown in Figure 6 in which it makes contact with a fixed contact 0. The said switch is electrically connected to the positive pole of a source of electrical supply D through a firing key E and the contact 0 is electrically connected to the contact arm A The contact a is electrically connected to the positive pole of the source of supply D and the coil C is electrically connected to the contact arm A and to the contact arm B.

In the firing position (Figure 6) current flows through the key E, the contact (2 the arm A the coil C the arm B and its contact b to the negative pole of the source of supply D, thereby energizing the said coil to bring the switch arm C against its contact c; The firing current can then pass through two local circuits one containing the switch C and the other the arm A If the gun has not fired by the time the commutator A has moved to shift the arm A away from its contact a current will still pass through the coil C and through the cartridge as will be apparent from Figure 6 and will continue to pass until the gun fires whereupon the circuits are broken by the movement of the arm B away from the contact b. In consequence of the deenergization of the coil C the switch arm C moves away from its contact 0. This is the condition shown in Figure 7. On the return of the gun breech mechanism to the firing position the arm B is again moved against its contact 6. Until the commutator A again assumes the position shown in' Figure 6 permitting firing to take place, the current cannot pass through the cartridge owing to the position occupied by the switch arm C, but as soon as the arm A is permitted to come against its contact a the switch arm moves into the position shown in Figure 6 and the circuit is completed as aforesaid.

The aforesaid firing key E is a simple switch arranged in one of the main leads from the source of supply D and when this key is moved into the safe position shown in Figure 8 the circuits are completely broken and the gun therefore cannot fire.

The arrangement shown in Figure 9 is generally similar to that of Figures 6, 7 and 8 except that the firing circuit contains an electro-magnet B serving to release the striker or firing pin of the gun.

What I claim and desire to secure by Letters Patent of the United States is 1. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a firing circuit, a device operating at predetermined times in accordance with the position of the propeller blades 1n relation to the line of fire of the gun, a device operating in accordance with whether the gun is ready or is unready to fire, and means for rendering said firing circuit operatlve to fire the gun by the conjoint action of said devices and for then maintaining said circuit operative so long as the second-mentioned device is in the ready position irrespective of the position to which the first mentioned device has moved in the interval.

2. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated at' predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which said contacts are located, a normally open firing circuit for the gun, and means for closing said-firing circuit by the conjoint action of said contacts and for maintaining it closed imtil the second-mentioned contact is operated by the firing of the gun.

3. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated at predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which said contacts are located, a firing circuit for the gun, a normally open switch in said firin circuit and means for closing said switch y the conjoint action of said contacts and or maintaining it closed until the second-mentioned contact is operated by the firing of the gun.

4. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated at predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which said contacts are located, a normally open firing circuit for the gun, means for closing said firing circuit when the first-mentioned contact and the second mentioned contact are open at one and the same time and for maintaining said firing circuit closed until the second-mentioned contact is closed by the firing of the gun.

5. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated at predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controllin circuit in which said contacts are locate a firing circuit for the gun, a normally open switch in said firing circuit, and means for closing said switch when the first-mentioned contact and the second-mentioned contact are open at one and the same time and for maintaining said switch closed until the second-mentioned contact is closed by the firing of the gun.

6. cans for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated at predetermined times'in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which said contacts are located, a normally open firing circuit for the gun, said circuit including the firing element of an electrically fired cartridge and means for closing said firing circuit by the conjoint action of said contacts and for maintaining it closed until the gun has fired.

7. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated at predetermined times in accordance with the position in relation to the line of fire of the gun,

' by the mechanism of the gun, a controlling circuit in which said contacts are located, a firing circuit for the gun, said circuit including the firing element of an electrically fired cartridge, a normally open switch in said firing circuit and means for closing said switch by the conjoint action of said contacts and for maintaining it closed until the second-mentioned contact is operated by the firing of the gun.

8. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated at predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which saidcontacts are located, a normally open firing circuit for the gun, said circuit including an electro-magnetically operated device for releasing the firing mechanism of a gun using percussive firing mechanism and means for closing said firing circuit by the conjoint action of said contacts and for maintaining it closed until the second-mentioned contact is operated by the firin of the gun.

9. Means for electrically controlling the fire of "automatic guns carried by aircraft, comprising a contact operated at predetermined times in accordance with the position -of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which said contacts are located, a firing circuit for the gun, said circuit including an electro-magnetically operated device for releasing the firing mechanism of a gun using percussive firing mechanism, a normally open switch in said firing circuit and means for closing said switch by the conjoint action of said contacts and for maintaining it closed until. the second-mew tioned contact is operated by the firing of the gun.

10. Means for electrieally controlling the fire of automatic guns carried by aircraft, comprising a contact operated at predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which said contacts are located, a normally open firing circuit for the gun, means for closing said firing circuit, when the first-mentioned contact and the secondmentioned contact are closed at one and the same time and for maintaining said firin circuit closed until the second-mentione contact is opened by the firing of the gun.

11. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated at predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which said contacts are located, firing circuit for the gun, a normally open switch in said firing circuit, and means for closing said switch when the first-mentioned contact and the second-mentioned contact are closed at one and the same time and for maintaining said switch closed until the second-mentioned contact is opened by thefiring of the gun.

12. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated at predeter mined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which said contacts are located, a normally open firing circuit for the gun, said circuit including the firing element of an electrically fired cartridge, means for closing said firing circuit by the conjoint closing of said contacts and for maintainin it closed until the gun has fired.

13. cans for electrically controlling the fire of automatic guns'carried by aircraft, comprising a contact operated at predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated b the mechanism of the gun, a controlling circuit in which said contacts are located, a firing circuit for the gun, said circuit including the firing element of an electrically fired cartridge, a normally open switch in said firing circuit and means for closing said switch by the conjoint closing of said contacts and for maintaining it closed until the second-mentioned contact is opened by the firing of the gun.

14. Means for electrically controlling the fire of automatic guns carried by aircraft, comprising a contact operated by predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated by the mechanism of the gun, a controlling circuit in which said contacts are located, a normally open firing circuit for the gun, said circuit including an electromagnetically operated device for releasing the firingmechanism of a gun using percussive firing mechanism, means for closing said firing circuit by the conjoint closing of said contacts and for maintaining it closed until the second mentioned contact is opened by the firing of the gun.

15. Means for electrically controlling the fire of automatic guns caried by aircraft, comprising a contact operated at predetermined times in accordance with the position of the propeller blades in relation to the line of fire of the gun, a contact operated comprising a contact operated atpredeterby the mechanism of the gun, a controlling mined times in accordance with the posicircuit 'in which said contacts are located, tion of the propeller blades in relation to firing circuit for the gun, said circuit inthe line of fire of the gun, a contact oper- 5 eluding an electrolnagnetically operated at-ed by the mechanism of the gun, a cona device for releasing the firing mechanism trolling circuit in which said contacts are of a gun using percussive firing mechanism, located, a normally open firing circuit for a normally open switch in said firing cirthe gun, means for closing said firing circuit and means for closing said switch by cuit by the conjoint action of said contacts 10 the conjoint Closing of said contacts and and for maintaining it closed until the secfor maintaining it closed until the second- 0nd mentioned contact is operated by the mentioned contact is opened by the firing firing of the gun, and a firing key for simul- Of the g m taneously controlling both Said circuits.

16. Means for electrically controlling the 15 fire of automatic guns carried by aircraft, OWEN DAVID LUCAS. 

